Dear Naveen,
From the screenshot you have posted, I believe you are trying to change the recon account from One account type to another
e.g vendor recon to customer or vice versa or Vendor/customer recon to Asset. ( be absolutely sure before changing this, since the same would have been updated in Vendor or customer or asset master respectively based on it's account type.
Note:
1. you can do the same only if the account has ZERO balance, to make balance to zero you cannot post JV as it is a Recon, direct posting from FI (JV) cannot be done. Hence clear the open item by making payment or receipt.
2. tick the check box, balance in local currency in control tab of the accont.
3. then save , system will not through the error.
Regards,
M S Lokesh